November 23, 2020

With a correlation of 0.9608654 between the actual and the predicted two-party popular vote for each state. The average difference between the actual and predicted two-party vote shares was -0.334%. That is, on average, Joe Biden underperformed his predicted vote share by -0.334 percentage points relative to the forecast.

State Actual Democratic Two-Party Vote Share Predicted Democratic Two-Party Vote Share Error
NY 56.86227 69.61151 -12.7492349
RI 60.50962 69.52752 -9.0179003
HI 65.03633 72.32903 -7.2927031
LA 40.53556 33.93166 6.6039010
SC 44.07339 37.81854 6.2548501
DE 59.62674 65.87647 -6.2497293
AR 35.78383 29.62813 6.1556991
AK 44.71671 40.02248 4.6942271
NJ 57.95494 62.50579 -4.5508461
CT 60.17662 64.60562 -4.4289997
CA 65.11285 69.50769 -4.3948411
WA 59.96097 64.18870 -4.2277291
MA 66.75495 70.77922 -4.0242638
ND 32.78259 36.80377 -4.0211801
OR 58.33414 62.25845 -3.9243061
NE 40.24716 44.02699 -3.7798311
WV 30.19374 33.80620 -3.6124615
KS 42.25143 38.65813 3.5932950
MN 53.63371 50.05711 3.5765990
MS 40.59077 37.20396 3.3868054
GA 50.14226 47.01611 3.1261463
ME 55.14282 52.09217 3.0506449
SD 36.56522 39.42158 -2.8563608
AZ 50.15683 47.34474 2.8120875
MT 41.60337 38.79975 2.8036197
MO 42.06354 39.50587 2.5576671
AL 37.03289 34.62090 2.4119937
KY 36.79758 34.47128 2.3263011
IN 41.79335 39.56968 2.2236715
VA 55.15147 57.35345 -2.2019778
NV 51.22312 49.36777 1.8553463
TN 38.11647 36.32844 1.7880338
NM 55.51577 53.81917 1.6966043
CO 56.93974 58.48604 -1.5463005
UT 39.31077 37.82175 1.4890258
NC 49.31625 48.10486 1.2113973
IL 58.45485 59.62805 -1.1732022
IA 45.81652 46.91440 -1.0978824
VT 68.29919 67.26910 1.0300846
MI 51.36015 50.53204 0.8281138
NH 53.74888 53.06014 0.6887330
WY 27.51957 26.85758 0.6619846
FL 48.30525 48.95294 -0.6476975
MD 66.62085 67.16643 -0.5455827
OK 33.05996 32.60532 0.4546372
TX 47.12886 46.69227 0.4365935
ID 34.12328 33.75413 0.3691501
PA 50.54056 50.68815 -0.1475896
OH 45.85491 45.99202 -0.1371140
WI 50.31728 50.35326 -0.0359886

The exact 2020 outcomes actually happened in 53 of my simulations. To put that into perspective, my point prediction occurred in 5080 of my simulations, which equates to 0.051%. Forecasters cannot predict the election outcome with absolute certainty, but models provide a range of possible scenarios. This model successfully anticipated a close Electoral Race with a large popular vote margin, and the actual outcome occurred more than a handful of times in my simulations. It was not the most likely outcome, but neither is rolling any given number on a die.

## # A tibble: 1 x 2
##   d_pv2p r_pv2p
##    <dbl>  <dbl>
## 1  0.519  0.481
Model Mean Error Root Mean Squared Error Classification Accuracy Missed States
Kayla Manning -0.2915302 3.901948 94 AZ, GA, NV
The Economist -2.3310087 2.803927 96 FL, NC
FiveThirtyEight -2.4447961 3.019431 96 FL, NC